Effects of whey protein and casein plus leucine on diaphragm the mTOR pathway of sedentary, trained rats

Effects of Leucine Administration in Sarcopenia: A Randomized and Placebo-controlled Clinical Trial

Treating sarcopenia in older individuals remains a challenge, and nutritional interventions present promising approaches in individuals that perform limited physical exercise. We assessed the efficacy of leucine administration to evaluate whether the regular intake of this essential amino acid can improve muscle mass, muscle strength and functional performance and respiratory muscle function in institutionalized older individuals. The study was a placebo-controlled, randomized, double-blind design in fifty participants aged 65 and over (ClinicalTrials.gov identifier NCT03831399). The participants were randomized to a parallel group intervention of 13 weeks’ duration with a daily intake of leucine (6 g/day) or placebo (lactose, 6 g/day). The primary outcome was to study the effect on sarcopenia and respiratory muscle function. The secondary outcomes were changes in the geriatric evaluation scales, such as cognitive function, functional impairment and nutritional assessments. We also evaluated whether leucine administration alters blood analytical parameters and inflammatory markers. Administration of leucine was well-tolerated and significantly improves some criteria of sarcopenia in elderly individuals such as functional performance measured by walking time (p = 0.011), and improved lean mass index. For respiratory muscle function, the leucine-treated group improved significantly (p = 0.026) in maximum static expiratory force compared to the placebo. No significant effects on functional impairment, cognitive function or nutritional assessment, inflammatory cytokines IL-6, TNF-alpha were observed after leucine administration compared to the placebo. The use of l-leucine supplementation can have some beneficial effects on sarcopenia and could be considered for the treatment of sarcopenia in older individuals.

Protein digestion of different protein sources using the INFOGEST static digestion model

In vitro digestion systems are valuable tools for understanding and monitoring the complex behavior of food degradation during digestion, thus proving to be good candidates for replacing in vivo assays. The aim of the present work was to study protein hydrolysis in a selection of different protein sources using the harmonized INFOGEST static protocol: three isolated proteins (collagen, zein, and whey protein) and five foods (sorghum flour, wheat bran cereals, peanuts, black beans, and pigeon peas). The proteins of all the substrates were analyzed by SDS-PAGE and HPLC-MS/MS. Individual amino acid composition was analyzed by high-performance liquid chromatography (HPLC). EAA/NEAA (essential amino acids/ nonessential amino acids) ratios in the substrates from low to high were as follows: wheat bran cereals, peanuts, collagen, zein, whey protein, sorghum, pigeon peas, and black beans. The results revealed sorghum, whey protein, and zein as good sources of BCAA. In all substrates, no intact protein from the substrates was visually detected by SDS-PAGE after the intestinal phase of in vitro digestion with the INFOGEST protocol. However, digestion-resistant peptides were detected in all substrates after the intestinal digestion phase. Protein hydrolysis was high in whey protein isolate and pigeon pea and low for wheat bran cereals and bovine collagen.

Comparison of the Effects of Soy Protein and Whey Protein Supplementation during Exercise: a Systematic Review

AbstractThe interest of the supplementation market for the soy protein consumption  to optimize physical and metabolic performance after exercise is increasing. However, evidence suggests that the  soy protein ingestion has lower anabolic properties when compared with whey protein. The purpose of this systematic review was to compare the effects of whey protein and soy protein supplementation on the  muscle functions maintenance after exercise. This review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles were searched for in the Pubmed database and included studies comparing the effects of soy protein and whey protein consumption on protein synthesis, lean mass gain and oxidative stress reduction in response to endurance or resistance training. Thirteen trials were included in this review. The results showed that the whey protein consumption is superior to that of soy protein with respect to protein synthesis and lean mass gain, but soy protein showed superior results in reducing oxidative stress. Future research comparing both soy and whey protein are needed to define protein source to be used in nutritional interventions to protein synthesis, lean mass gain and oxidative stress in different populations. Keywords: Soybean Proteins. Milk Proteins. Protein Biosynthesis. Hypertrophy. ResumoO interesse do mercado de suplementação pelo consumo de proteína de soja para otimizar o desempenho físico e metabólico após o exercício está aumentando. No entanto, evidências sugerem que a ingestão da proteína de soja tem propriedades anabólicas mais baixas quando comparada à proteína do soro do leite. O objetivo desta revisão sistemática foi comparar os efeitos da suplementação com whey protein e proteína de soja na manutenção das funções musculares após o exercício. Esta revisão foi realizada usando os Itens de Relatório Preferidos para Revisões Sistemáticas e Meta-Análises (PRISMA). Os artigos foram pesquisados na base de dados Pubmed e incluíram estudos comparando os efeitos da proteína de soja e do consumo de proteínas do soro na síntese protéica, ganho de massa magra e redução do estresse oxidativo em resposta ao treinamento de resistência ou resistência. Treze ensaios foram incluídos nesta revisão. Os resultados mostraram que o consumo de proteína de soro é superior ao da proteína de soja em relação à síntese protéica e ao ganho de massa magra, mas a proteína de soja apresentou resultados superiores na redução do estresse oxidativo. Pesquisas futuras comparando a soja e a proteína do soro do leite são necessárias para definir a fonte protéica a ser usada em intervenções nutricionais para a síntese protéica, ganho de massa magra e estresse oxidativo em diferentes populações. Palavras-chave: Proteínas de Soja. Proteínas do Leite. Biossíntese de Proteínas. Hipertrofia.

Bioactivity of food peptides: biological response of rats to bovine milk whey peptides following acute exercise

Background: Several physiologically beneficial effects of consuming a whey protein hydrolysate (WPH) have been attributed to the greater availability of bioactive peptides.

Aims: The aim was to investigate the effect of four branched-chain amino acid- (BCAA-)containing dipeptides, present in WPH, on immune modulation, stimulation of HSP expression, muscle protein synthesis, glycogen content, satiety signals and the impact of these peptides on the plasma free amino acid profiles.

Methods: The animals were divided in groups: control (rest, without gavage), vehicle (water), L-isoleucyl-L-leucine (lle-Leu), L-leucyl-L-isoleucine (Leu-lle), L-valyl-Lleucine (Val-Leu), L-leucyl-L-valine (Leu-Val) and WPH. All animals were submitted to acute exercise, except for control.

Results: lle-Leu stimulated immune response, hepatic and muscle glycogen and HSP60 expression, whereas Leu-Val enhanced HSP90 expression. All dipeptides reduced glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide, no changes were observed on leptin. All peptides inhibited NF-kB expression. The plasma amino acid time-course showed peptide-specific and isomer-specific metabolic features, including increases of the BCAAs.

Conclusion: The data indicate that lle-Leu was effective to attenuate immune-suppression exercise-induced, promoted glycogen content and stimulated anti-stress effect (HSP). Furthermore, Leu-Val increased HSP90, p-4EBP1, p-mTOR and p-AMPK expression. The data suggest the involvement of these peptides in various beneficial functions of WPH consumption.

Whey protein hydrolysate increases translocation of GLUT-4 to the plasma membrane independent of insulin in wistar rats

Whey protein (WP) and whey protein hydrolysate (WPH) have the recognized capacity to increase glycogen stores. The objective of this study was to verify if consuming WP and WPH could also increase the concentration of the glucose transporters GLUT-1 and GLUT-4 in the plasma membrane (PM) of the muscle cells of sedentary and exercised animals. Forty-eight Wistar rats were divided into 6 groups (n = 8 per group), were treated and fed with experimental diets for 9 days as follows: a) control casein (CAS); b) WP; c) WPH; d) CAS exercised; e) WP exercised; and f) WPH exercised. After the experimental period, the animals were sacrificed, muscle GLUT-1 and GLUT-4, p85, Akt and phosphorylated Akt were analyzed by western blotting, and the glycogen, blood amino acids, insulin levels and biochemical health indicators were analyzed using standard methods. Consumption of WPH significantly increased the concentrations of GLUT-4 in the PM and glycogen, whereas the GLUT-1 and insulin levels and the health indicators showed no alterations. The physical exercise associated with consumption of WPH had favorable effects on glucose transport into muscle. These results should encourage new studies dealing with the potential of both WP and WPH for the treatment or prevention of type II diabetes, a disease in which there is reduced translocation of GLUT-4 to the plasma membrane.